scholarly journals Investigation of a CDDW Hamiltonian to Explore Possibility of Magneto-Quantum Oscillations in Electronic Specific Heat of Hole-Doped Cuprates

2010 ◽  
Vol 2010 ◽  
pp. 1-11
Author(s):  
Partha Goswami ◽  
Manju Rani
Keyword(s):  
Specific Heat ◽  
Chemical Potential ◽  
Density Wave ◽  
Mean Field ◽  
Anisotropy Parameter ◽  
Zero Magnetic Field ◽  
Electronic Specific Heat ◽  
Mean Field Model ◽  
Quantum Oscillations ◽  
Disorder Potential

We investigate a chiral d-density wave (CDDW) mean field model Hamiltonian in the momentum space suitable for the hole-doped cuprates, such as YBCO, in the pseudogap phase to obtain the Fermi surface (FS) topologies, including the anisotropy parameter() and the elastic scattering by disorder potential (). For , with the chemical potential eV for 10% doping level and (where eV is the first neighbor hopping), at zero/non-zero magnetic field (), the FS on the first Brillouin zone is found to correspond to electron pockets around antinodal regions and barely visible patches around nodal regions. For , we find Pomeranchuk distortion of FS. We next relate our findings regarding FS to the magneto-quantum oscillations in the electronic specific heat. Since the nodal quasiparticle energy values for are found to be greater than for , the origin of the oscillations for nonzero corresponds to the Fermi pockets around antinodal regions. The oscillations are shown to take place in the weak disorder regime (eV) only.

Modification of charge density wave fluctuations by charge perturbations

2002 ◽  
Vol 12 (9) ◽  
pp. 77-78
Author(s):  
S. N. Artemenko
Keyword(s):  
Electric Field ◽  
Linear Response ◽  
Chemical Potential ◽  
Density Wave ◽  
Mean Field ◽  
Phase Fluctuations ◽  
Fluctuation Dissipation ◽  
Fluctuation Dissipation Theorem ◽  
The Mean ◽  
Field Transition

Spectral density of fluctuations of the CDW phase are calculated taking into account electric field induced by phase fluctuations. The approach based upon the fluctuation-dissipation theorem (FDT) combined with equations of linear response of the CDW conductor is used. Fluctuating electric field is found to suppress fluctuations of the phase, while fluctuations of the electric potential are sizeable. This suggests that transition from the CDW to the normal state (which is usually observed well below the mean-field transition temperature) may he provoked by fluctuations of the chemical potential, rather than by destruction of the CDW coherence between conducting chains due to phase fluctuations.

scholarly journals Impact of jamming criticality on low-temperature anomalies in structural glasses

2019 ◽  
Vol 116 (28) ◽  
pp. 13768-13773 ◽  
Author(s):  
Silvio Franz ◽  
Thibaud Maimbourg ◽  
Giorgio Parisi ◽  
Antonello Scardicchio
Keyword(s):  
Low Temperature ◽  
Specific Heat ◽  
Field Model ◽  
Analytic Solution ◽  
Mean Field ◽  
Universality Class ◽  
Amorphous Solids ◽  
Anomalous Behavior ◽  
Marginal Stability ◽  
Mean Field Model

We present a mechanism for the anomalous behavior of the specific heat in low-temperature amorphous solids. The analytic solution of a mean-field model belonging to the same universality class as high-dimensional glasses, the spherical perceptron, suggests that there exists a cross-over temperature above which the specific heat scales linearly with temperature, while below it, a cubic scaling is displayed. This relies on two crucial features of the phase diagram: (i) the marginal stability of the free-energy landscape, which induces a gapless phase responsible for the emergence of a power-law scaling; and (ii) the vicinity of the classical jamming critical point, as the cross-over temperature gets lowered when approaching it. This scenario arises from a direct study of the thermodynamics of the system in the quantum regime, where we show that, contrary to crystals, the Debye approximation does not hold.

scholarly journals ON d+id DENSITY WAVE AND SUPERCONDUCTING ORDERINGS IN HOLE-DOPED CUPRATES

2013 ◽  
Vol 27 (13) ◽  
pp. 1330008
Author(s):  
PARTHA GOSWAMI ◽  
AJAY PRATAP SINGH GAHLOT ◽  
PANKAJ SINGH
Keyword(s):  
Chemical Potential ◽  
Density Wave ◽  
Mean Field ◽  
Spectral Weight ◽  
Quasi Particle ◽  
Scattering Rate ◽  
Consistent Manner ◽  
Single Particle Excitation ◽  
The Mean ◽  
Competing Orders

The d+id-density wave (chiral DDW) order, at the anti-ferromagnetic wave vector Q = (π, π), is assumed to represent the pseudo-gap (PG) state of a hole-doped cuprate superconductor. The pairing interaction U(k, k′) required for d+id ordering comprises of (Ux2-y2(k, k′), Uxy(k, k′)), where [Formula: see text] and [Formula: see text] with U1 > U2. The d-wave superconductivity (DSC), driven by an assumed attractive interaction of the form [Formula: see text] where V1 is a model parameter, is discussed within the mean-field framework together with the d+id ordering. The single-particle excitation spectrum in the CDDW + DSC state is characterized by the Bogoluibov quasi-particle bands — a characteristic feature of SC state. The coupled gap equations are solved self-consistently together with the equation to determine the chemical potential (μ). With the pinning of the van Hove-singularities close to μ, one is able to calculate the thermodynamic and transport properties of the under-doped cuprates in a consistent manner. The electron specific heat displays non-Fermi liquid feature in the CDDW state. The CDDW and DSC are found to represent two competing orders as the former brings about a depletion of the spectral weight (and Raman response function density) available for pairing in the anti-nodal region of momentum space. It is also shown that the depletion of the spectral weight below Tc at energies larger than the gap amplitude occurs. This is an indication of the strong-coupling superconductivity in cuprates. The calculation of the ratio of the quasi-particle thermal conductivity αxx and temperature in the superconducting phase is found to be constant in the limit of near-zero quasi-particle scattering rate.

An Equilibrium Based Mean-Field Model for Diffusion in Solids With a Distributed Density of States

1997 ◽  
Vol 469 ◽  
Author(s):  
A. J. Franz ◽  
J. L. Gland
Keyword(s):  
Amorphous Silicon ◽  
Density Of States ◽  
Chemical Potential ◽  
Energy Levels ◽  
Mean Field ◽  
Diffusion In Solids ◽  
Mean Field Model ◽  
Discrete Energy ◽  
Mobile Species

ABSTRACTDetermination of transport mechanisms and energetics in amorphous silicon presents an interesting modeling challenge. Transport in amorphous silicon films is likely to involve energetically distributed traps and mobile species, as in the case of hydrogen and electron diffusion. Detailed kinetic models using discrete energy levels have been developed, however, the density of states of the diffusing species in amorphous silicon is likely to be continuous and distributed, due to the amorphous nature of the films. We have developed a mean-field, equilibrium based model which utilizes a continuous density of states for the diffusing species. The transport in amorphous silicon is modeled as a function of a gradient in the quasi-chemical potential, rather than concentration, of the diffusing species. The model is applicable when the local equilibration processes are fast relative to the transport process. This approach is extremely numerically efficient, as well as flexible, allowing for modeling of tracer experiments, such as deuterium diffusion in a-Si:H films, and possible changes in density of states with time, temperature, and diffusing species concentration. We demonstrate the utility of the model by simulating hydrogen evolution from a-Si:H films.

scholarly journals STRANGENESS PRODUCTION AT FINITE TEMPERATURE AND BARYON DENSITY IN AN EFFECTIVE RELATIVISTIC MEAN FIELD MODEL

2012 ◽  
Vol 21 (03) ◽  
pp. 1250028
Author(s):  
F. IAZZI ◽  
R. INTROZZI ◽  
A. LAVAGNO ◽  
D. PIGATO ◽  
M. H. YOUNIS
Keyword(s):  
Field Model ◽  
Chemical Potential ◽  
Mean Field ◽  
Baryon Density ◽  
Strangeness Production ◽  
Coupling Scheme ◽  
Mean Field Model ◽  
Relativistic Mean Field ◽  
Kaon Condensation ◽  
Wide Range

We study the strangeness production in hot and dense nuclear medium, by requiring the conservation of the baryon density, electric charge fraction and zero net strangeness. The hadronic equation of state is investigated by means of an effective relativistic mean field model, with the inclusion of the full octet of baryons and kaon mesons. Kaons are considered taking into account of an effective chemical potential depending on the self-consistent interaction between baryons. The obtained results are compared with a minimal coupling scheme, calculated for different values of the anti-kaon optical potential and with noninteracting kaon particles. In this context, we also consider the possible onset of the kaon condensation for a wide range of temperatures and baryon densities.

scholarly journals Polymer-Assisted Condensation: A Mechanism for Hetero-Chromatin Formation and Epigenetic Memory

2021 ◽  
Author(s):  
Jens-Uwe Sommer ◽  
Helmut Schiessel ◽  
Holger Merlitz
Keyword(s):  
Chemical Potential ◽  
Liquid Mixture ◽  
Essential Feature ◽  
Mean Field ◽  
Mean Field Model ◽  
Solvent Phase ◽  
Polymer Volume ◽  
Potential Trap ◽  
Fluctuation Effects ◽  
Dynamics Simulations

We consider the formation of droplets from a 2-component liquid mixture induced by a large polymer chain that has preferential solubility with one of the components. We assume that the liquid mixture is in a fully miscible state, but far above the critical interaction limit of the two species. We show that the polymer coil acts as a chemical potential trap, which can shift the mixture inside the polymer volume into the partially miscible state and thus triggers the formation of a polymer-bound droplet of the preferred solvent phase which we denote as polymer-assisted condensation (PAC). We propose a simple mean-field model which can predict the essential feature of PAC and perform molecular-dynamics simulations to show that the predicted phase behavior is robust against fluctuation effects. Our model aims to understand the formation of macromolecular condensates inside the cell nucleus, such as those formed by heterochromatin 1 (HP1). We propose that such droplets organize the spatial structure of chromatin into hetero- and euchromatin and ensure the propagation of epigenetic information through the cell generations.

scholarly journals On the characterization of vortex configurations in the steady rotating Bose–Einstein condensates

2017 ◽  
Vol 473 (2208) ◽  
pp. 20170602 ◽  
Author(s):  
P. G. Kevrekidis ◽  
D. E. Pelinovsky
Keyword(s):  
Field Model ◽  
Chemical Potential ◽  
Mean Field ◽  
Repulsive Interaction ◽  
Mean Field Model ◽  
Ode System ◽  
Steady Rotation ◽  
Bose Einstein ◽  
Good Agreement

Motivated by experiments in atomic Bose–Einstein condensates (BECs), we compare predictions of a system of ordinary differential equations (ODEs) for dynamics of one and two individual vortices in the rotating BECs with those of the Gross–Pitaevskii mean-field model written as a partial differential equation (PDE). In particular, we characterize orbitally stable vortex configurations in a symmetric harmonic trap due to a cubic repulsive interaction and a steady rotation. The ODE system is analysed in detail and the PDE model is approximated numerically. Good agreement between the two models is established in the semi-classical (Thomas–Fermi) limit that corresponds to the BECs at large values of the chemical potential.

Physical Properties of Li2Pd3B and Li2Pt3B Superconductors

2007 ◽  
Vol 561-565 ◽  
pp. 2079-2082 ◽  
Author(s):  
Hiroyuki Takeya ◽  
Shigeru Kasahara ◽  
Mohammed El Massalami ◽  
Takashi Mochiku ◽  
Kazuto Hirata ◽  
...  
Keyword(s):  
Specific Heat ◽  
Relaxation Method ◽  
Zero Magnetic Field ◽  
Bcs Theory ◽  
Superconducting Gap ◽  
Electronic Specific Heat ◽  
Superconducting Transition ◽  
Critical Fields ◽  
Resistivity Measurements ◽  
Upper Critical Fields

Superconductivity in two Li-containing compounds of Li2Pd3B and Li2Pt3B was recently discovered. These materials, showing the superconducting transition at 7.2 K and 2.6 K, respectively, have the same cubic structure (P4332) composed of distorted octahedrons without mirror or inversion symmetry along any directions. This is a very interesting feature of those materials in relation to the symmetry of superconductivity. Resistivity measurements in magnetic fields gave their upper critical fields, Hc2(0) = 45 kOe and 19 kOe, respectively. Their specific heat was measured using a heat-pulse relaxation method. The Sommerfeld coefficient (γ) and Debye temperature (θD) terms of Li2Pd3B were given as γ=9.5 mJmol-1K-2 and θD=228 K . The value of C/γT at Tc was calculated to be 1.7. In the same manner, those parameters were described for Li2Pt3B as γ=9.6 mJmol-1K-2, θD=240 K, and C/γTc =0.75, respectively. Since C/γTC in the weakcoupling limit by the BCS theory is 1.43, the value of 1.7 for Li2Pd3B is slightly higher. The electronic specific heat of Li2Pd3B at a zero magnetic field follows the typical exponetial behavior discribed in the BCS theory, while that of Li2Pt3B shows quadratic behavior. This result suggests the line nodes exist in the superconducting gap of Li2Pt3B driven by the spin-orbit interaction.

scholarly journals Relativistic selfinteracting particle­-antiparticle system of bosons

2020 ◽  
Vol 28 (2) ◽  
pp. 3-18
Author(s):  
D. Anchishkin ◽  
V. Gnatovskyy ◽  
D. Zhuravel ◽  
V. Karpenko
Keyword(s):  
Phase Transition ◽  
Thermodynamic Properties ◽  
Specific Heat ◽  
Temperature Interval ◽  
Thermodynamic Functions ◽  
Field Model ◽  
Mean Field ◽  
Einstein Condensate ◽  
Mean Field Model ◽  
The Mean

Thermodynamic properties of a system of an interacting boson particles and antiparticles at high tem­peratures are studied within the framework of the thermodynamically consistent Skyrme-­like mean-­field model. The mean field contains both attractive and repulsive terms. Self­-consistency relations between the mean field and thermodynamic functions are derived. We assume a conservation of the isospin density for all temperatures. It is shown that, independently of the strength of the attractive mean field, at the critical tem­perature Tc the system undergoes the phase transition of second order to the Bose­-Einstein condensate, which exists in the temperature interval 0 ≤ T ≤ Tc . It is obtained that the condensation represents a discontinuity of the derivative of the specific heat at T = Tc .

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